:root {
  --bg-start: #0d1b3c;
  --bg-mid: #152b63;
  --bg-end: #221f52;
  --surface: #ffffff;
  --surface-soft: rgba(255, 255, 255, 0.9);
  --text-main: #172033;
  --text-soft: #5d6780;
  --line: rgba(120, 142, 189, 0.2);
  --primary: #2f67ff;
  --primary-deep: #2146b8;
  --accent: #6da7ff;
  --shadow: 0 20px 45px rgba(10, 26, 64, 0.16);
  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --container: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
  color: var(--text-main);
  background:
    radial-gradient(circle at top left, rgba(120, 176, 255, 0.2), transparent 30%),
    linear-gradient(135deg, var(--bg-start), var(--bg-mid) 50%, var(--bg-end));
  min-height: 100vh;
  line-height: 1.75;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

.container {
  width: min(calc(100% - 40px), var(--container));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(18px);
  background: rgba(8, 16, 38, 0.72);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 78px;
}

.brand {
  color: #fff;
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.site-nav a {
  color: rgba(255, 255, 255, 0.82);
  padding: 10px 14px;
  border-radius: 999px;
  transition: background-color 0.25s ease, color 0.25s ease, transform 0.25s ease;
}

.site-nav a:hover,
.site-nav a.active {
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
  transform: translateY(-1px);
}

.nav-toggle {
  display: none;
  width: 46px;
  height: 46px;
  border: 0;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.08);
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: #fff;
  border-radius: 999px;
}

.hero,
.page-hero {
  padding: 72px 0 40px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: 28px;
  align-items: center;
}

.hero-copy,
.page-hero .container {
  color: #fff;
}

.eyebrow {
  margin: 0 0 12px;
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

.hero h1,
.page-hero h1 {
  margin: 0;
  font-size: clamp(2.4rem, 5vw, 4.4rem);
  line-height: 1.1;
}

.hero-subtitle {
  margin: 18px 0 14px;
  font-size: clamp(1.1rem, 2vw, 1.45rem);
  color: rgba(255, 255, 255, 0.92);
}

.hero-text,
.page-hero p:not(.eyebrow) {
  max-width: 700px;
  color: rgba(255, 255, 255, 0.8);
  font-size: 1.02rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 24px;
  border-radius: 999px;
  font-weight: 700;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--primary), #5697ff);
  box-shadow: 0 14px 28px rgba(47, 103, 255, 0.34);
}

.btn-secondary {
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.16);
}

.card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.72);
}

.hero-panel {
  padding: 30px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.97), rgba(245, 248, 255, 0.94));
}

.hero-panel h2 {
  margin: 12px 0 10px;
  font-size: 1.45rem;
}

.stat-chip {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(47, 103, 255, 0.1);
  color: var(--primary-deep);
  font-weight: 700;
  font-size: 0.95rem;
}

.feature-list {
  margin: 18px 0 0;
  padding-left: 20px;
  color: var(--text-soft);
}

.section {
  padding: 28px 0 40px;
}

.section-soft {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0));
}

.section-heading {
  margin-bottom: 24px;
  color: #fff;
}

.section-heading h2 {
  margin: 0 0 10px;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
}

.section-heading p:last-child {
  margin: 0;
  max-width: 760px;
  color: rgba(255, 255, 255, 0.76);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.topic-card {
  padding: 26px;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.topic-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 26px 50px rgba(10, 26, 64, 0.22);
}

.topic-card h3,
.faq-item h3,
.sidebar-card h3 {
  margin-top: 0;
}

.topic-card p,
.faq-item p,
.article-card p,
.sidebar-card,
.about-box p {
  color: var(--text-soft);
}

.topic-card span,
.text-link {
  color: var(--primary);
  font-weight: 700;
}

.faq-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.faq-item,
.about-box,
.article-card,
.sidebar-card {
  padding: 26px;
}

.about-box {
  display: grid;
  gap: 12px;
}

.page-main {
  padding-bottom: 26px;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 24px;
  align-items: start;
}

.article-card section + section {
  margin-top: 28px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.article-card h2,
.faq-page-item h2 {
  margin-top: 0;
  margin-bottom: 10px;
}

.sidebar-card {
  position: sticky;
  top: 100px;
}

.narrow-stack {
  max-width: 860px;
}

.narrow-stack > * + * {
  margin-top: 20px;
}

.single-column {
  max-width: 860px;
}

.site-footer {
  padding: 10px 0 32px;
}

.footer-wrap {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding-top: 18px;
  color: rgba(255, 255, 255, 0.78);
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 0.95rem;
}

.footer-wrap a {
  color: #fff;
}

@media (max-width: 980px) {
  .hero-grid,
  .article-layout,
  .card-grid,
  .faq-list {
    grid-template-columns: 1fr;
  }

  .sidebar-card {
    position: static;
  }
}

@media (max-width: 860px) {
  .nav-toggle {
    display: inline-block;
    flex-shrink: 0;
  }

  .site-nav {
    position: absolute;
    top: 78px;
    left: 20px;
    right: 20px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
    padding: 16px;
    background: rgba(8, 16, 38, 0.96);
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 22px 50px rgba(0, 0, 0, 0.22);
  }

  .site-nav.open {
    display: flex;
  }

  .site-nav a {
    border-radius: 14px;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(calc(100% - 28px), var(--container));
  }

  .hero,
  .page-hero {
    padding-top: 56px;
  }

  .hero-panel,
  .topic-card,
  .faq-item,
  .about-box,
  .article-card,
  .sidebar-card {
    padding: 22px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .footer-wrap {
    flex-direction: column;
  }
}